Abstract ID: 289

Dynamics of soil CO2 at storm, diurnal and seasonal scales

Soil CO2 is known to respond rapidly to changes in soil moisture in tropical forests. However, the within-soil dynamics are not fully captured by chamber-based measurements of soil respiration. We installed infrared gas analyzers directly in the soil profile to investigate soil CO2 dynamics on a continuous basis, and coupled these real time in situ measurements with co-located measurements of soil moisture and temperature. We found that rapid increases in soil moisture following rain events were followed by rapid increases in soil CO2 at 10 cm depth, even during near-daily precipitation during the rainy season. Augmented CO2 concentrations in the upper soil (15 cm depth) were found to persist even after soil moisture had returned to pre-event levels. At 1 m depth, however, soil CO2 responses were dampened and lagged those of the near surface. At 4 m depth, no responses to precipitation events were noted. Nevertheless, diurnal uptake of soil moisture was found to influence CO2 concentrations at all depths. The soil CO2 dynamics of the deep soil were found to coincide with those at the terrestrial-aquatic interface of the small headwater catchments studied.

Session:  Carbon - The role of seasonality in carbon and water balance.

Presentation Type:  Poster